| 摘要 |
PURPOSE:To provide microcapsules which hold unstable hydrophobic materials stably with core materials by dispersing the hydrophobic materials in an aq. acidic soln. of styrene-maleic anhydride copolymers, adding precondensate of melamine and formalin thereto and changing reaction temp. in >=2 stages. CONSTITUTION:Hydrophobic materials are dispersed or emulsified in an aq. acidic soln. of styrene-maleic anhydride copolymers having <=7pH so as to form discontinuous fine particles. The copolymers are used at about 2-20pts.wt. based on 100pts.wt. the hydrophobic materials. Precondensate of about 1:>=1.5 ratio between melamine and formalin is added to the emulsified liquid to capsulate the hydrophobic materials while allowing melamine-formalin resins to form at about 50-80 deg.C. The capsule films formed by the above are intensified at >=81 deg.C, more preferably about 90-100 deg.C. Thus, the microcapsules having excellent heat resistance, solvent resistance and impact resistance are obtained. |
